Comprehensive characterization of Candida isolates in a given geographical area for the determination of prevalence and drug sensitivity

Abstract

Purpose: An alarming increase in Candidiasis infections has been observed worldwide and in India. This increase is attributed to increase in immune-compromised individuals and an increase in plethora of species causing the disease. The emergence of drug resistance of isolates has further worsened the situation. Materials & Methods: Candida isolates causing infections were obtained from patients and evaluated for their macroscopic and microscopic characteristics by colony morphology and staining procedures. The patients demography was also analyzed to identify any correlation between the isolates. Doubling time was determined to analyze growth characteristics of these isolates. Isolates were also characterized biochemically for their ability to assimilate carbon and nitrogen sources and for fermentative capabilities. Additionally, drug sensitivity profiles of these isolates were analyzed towards Azoles. Results: Demographic analysis of the isolates suggested that all age groups were affected by Candida via both albicans and non-albican species. The infections were not gender biased but majority isolates were obtained from urine samples suggesting Candida as an important species causing urine-genital infections. Macroscopic and microscopic analysis showed cream colored circular colonies with smooth surface and entire margins with cells in single and budding stage. The doubling time ranged between 40 mins to 180 mins with 81 mins being the average. Biochemical characterization showed sucrose to be the most metabolizable sugar with maximum fermentative capacity with glucose. Surprisingly, very low nitrogen assimilation capacity was observed with all the nitrogen sources tested (nitrate, urea and glycine). Drug sensitivity towards Azoles suggested almost 50% and 90% isolates were resistant to Fluconazole and Itraconazole respectively, the most common Azoles used against fungal infections in the current scenario. Conclusions: The results obtained from the study suggested differential characteristics of the isolates towards various parameters thereby indicating the relevance of isolate characterization, for appropriate control and prevention of the disease.